Demon Attack
Platform: Atari 2600
Region: USA
Media: Cartridge
Controller: Joystick
Genre: Shooter - Fixed
Gametype: Licensed
Release Year: 1982
Developer: Imagic
Publisher: Imagic
Players: 1 or 2 Alternating
Programmer: Rob Fulop
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Marooned on the ice planet Krybor, the player uses a laser cannon to destroy legions of demons that attack from above. Visually, the demons appear in waves similar to other space-themed shooters, but individually combine from the sides of the screen to the area above the player's cannon.

Each wave introduces new weapons with which the demons attack, such as long streaming lasers and laser clusters. Starting in Wave 5, demons also divide into two smaller, bird-like creatures that eventually attempt descent onto the player's cannon. Starting in Wave 9, the demons' shots follow directly beneath the monsters, making it difficult for the player to slip underneath to get in a direct shot.

Development: 

Demon Attack is based on the 1979 arcade shooter Galaxian.

The game was originally programmed to end after the 84th wave, as Fulop did not expect anyone to "wrap" the game. Two days after its initial release, a kid was able to beat the game. After this initial run of cartridges, Fulop went back and changed one line of code so that the game never ends, but never gets harder after the 84th wave.

Lawsuit: 

Demon Attack closely resembles the earlier arcade game Phoenix, prompting a lawsuit from Atari, who had purchased the latter's home video game rights. Imagic settled out of court, and Demon Attack went on to become the company's only hit title.

http://en.wikipedia.org/wiki/Demon_Attack
